Mechanically driven oscillating fans are old in the art. These fans are complicated and suffer the economic disadvantage of high cost and weighty structure due to the mechanical devices required to convert fan motor drive rotation into fan oscillation. This is especially true of larger fans.
Aerodynamically excited oscillating fans have been proposed in the art but the two degree of freedom horizontal oscillating mechanisms used to obtain reversing aerodynamic turning moments on the fan disk are overly complex and not practical.
Gyroscopically excited oscillating fans have been proposed in the art but the precession of the fan is conical requiring complicated gymbal mounts and not limited to an oscillation in a horizontal plane.
There is thus an established need for a self-excited oscillating fan having horizontal oscillations induced by means without the aid of complex mechanical devices.